From 4201e08f1dbb521e5555d96a3b6464a860466f5f Mon Sep 17 00:00:00 2001 From: Jordan Whited Date: Mon, 2 Oct 2023 14:41:04 -0700 Subject: [PATCH] device: distribute crypto work as slice of elements After reducing UDP stack traversal overhead via GSO and GRO, runtime.chanrecv() began to account for a high percentage (20% in one environment) of perf samples during a throughput benchmark. The individual packet channel ops with the crypto goroutines was the primary contributor to this overhead. Updating these channels to pass vectors, which the device package already handles at its ends, reduced this overhead substantially, and improved throughput. The iperf3 results below demonstrate the effect of this commit between two Linux computers with i5-12400 CPUs. There is roughly ~13us of round trip latency between them. The first result is with UDP GSO and GRO, and with single element channels. Starting Test: protocol: TCP, 1 streams, 131072 byte blocks [ ID] Interval Transfer Bitrate Retr Cwnd [ 5] 0.00-10.00 sec 12.3 GBytes 10.6 Gbits/sec 232 3.15 MBytes - - - - - - - - - - - - - - - - - - - - - - - - - Test Complete. Summary Results: [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 12.3 GBytes 10.6 Gbits/sec 232 sender [ 5] 0.00-10.04 sec 12.3 GBytes 10.6 Gbits/sec receiver The second result is with channels updated to pass a slice of elements. Starting Test: protocol: TCP, 1 streams, 131072 byte blocks [ ID] Interval Transfer Bitrate Retr Cwnd [ 5] 0.00-10.00 sec 13.2 GBytes 11.3 Gbits/sec 182 3.15 MBytes - - - - - - - - - - - - - - - - - - - - - - - - - Test Complete. Summary Results: [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 13.2 GBytes 11.3 Gbits/sec 182 sender [ 5] 0.00-10.04 sec 13.2 GBytes 11.3 Gbits/sec receiver Reviewed-by: Adrian Dewhurst Signed-off-by: Jordan Whited Signed-off-by: Jason A. Donenfeld --- device/channels.go | 8 ++++---- device/receive.go | 42 ++++++++++++++++++++-------------------- device/send.go | 48 +++++++++++++++++++++++----------------------- 3 files changed, 49 insertions(+), 49 deletions(-) diff --git a/device/channels.go b/device/channels.go index 039d8df..40ee5c9 100644 --- a/device/channels.go +++ b/device/channels.go @@ -19,13 +19,13 @@ import ( // call wg.Done to remove the initial reference. // When the refcount hits 0, the queue's channel is closed. type outboundQueue struct { - c chan *QueueOutboundElement + c chan *[]*QueueOutboundElement wg sync.WaitGroup } func newOutboundQueue() *outboundQueue { q := &outboundQueue{ - c: make(chan *QueueOutboundElement, QueueOutboundSize), + c: make(chan *[]*QueueOutboundElement, QueueOutboundSize), } q.wg.Add(1) go func() { @@ -37,13 +37,13 @@ func newOutboundQueue() *outboundQueue { // A inboundQueue is similar to an outboundQueue; see those docs. type inboundQueue struct { - c chan *QueueInboundElement + c chan *[]*QueueInboundElement wg sync.WaitGroup } func newInboundQueue() *inboundQueue { q := &inboundQueue{ - c: make(chan *QueueInboundElement, QueueInboundSize), + c: make(chan *[]*QueueInboundElement, QueueInboundSize), } q.wg.Add(1) go func() { diff --git a/device/receive.go b/device/receive.go index e24d29f..f0f37a1 100644 --- a/device/receive.go +++ b/device/receive.go @@ -220,9 +220,7 @@ func (device *Device) RoutineReceiveIncoming(maxBatchSize int, recv conn.Receive for peer, elems := range elemsByPeer { if peer.isRunning.Load() { peer.queue.inbound.c <- elems - for _, elem := range *elems { - device.queue.decryption.c <- elem - } + device.queue.decryption.c <- elems } else { for _, elem := range *elems { device.PutMessageBuffer(elem.buffer) @@ -241,26 +239,28 @@ func (device *Device) RoutineDecryption(id int) { defer device.log.Verbosef("Routine: decryption worker %d - stopped", id) device.log.Verbosef("Routine: decryption worker %d - started", id) - for elem := range device.queue.decryption.c { - // split message into fields - counter := elem.packet[MessageTransportOffsetCounter:MessageTransportOffsetContent] - content := elem.packet[MessageTransportOffsetContent:] + for elems := range device.queue.decryption.c { + for _, elem := range *elems { + // split message into fields + counter := elem.packet[MessageTransportOffsetCounter:MessageTransportOffsetContent] + content := elem.packet[MessageTransportOffsetContent:] - // decrypt and release to consumer - var err error - elem.counter = binary.LittleEndian.Uint64(counter) - // copy counter to nonce - binary.LittleEndian.PutUint64(nonce[0x4:0xc], elem.counter) - elem.packet, err = elem.keypair.receive.Open( - content[:0], - nonce[:], - content, - nil, - ) - if err != nil { - elem.packet = nil + // decrypt and release to consumer + var err error + elem.counter = binary.LittleEndian.Uint64(counter) + // copy counter to nonce + binary.LittleEndian.PutUint64(nonce[0x4:0xc], elem.counter) + elem.packet, err = elem.keypair.receive.Open( + content[:0], + nonce[:], + content, + nil, + ) + if err != nil { + elem.packet = nil + } + elem.Unlock() } - elem.Unlock() } } diff --git a/device/send.go b/device/send.go index cd8a2a0..e838c4e 100644 --- a/device/send.go +++ b/device/send.go @@ -385,9 +385,7 @@ top: // add to parallel and sequential queue if peer.isRunning.Load() { peer.queue.outbound.c <- elems - for _, elem := range *elems { - peer.device.queue.encryption.c <- elem - } + peer.device.queue.encryption.c <- elems } else { for _, elem := range *elems { peer.device.PutMessageBuffer(elem.buffer) @@ -447,32 +445,34 @@ func (device *Device) RoutineEncryption(id int) { defer device.log.Verbosef("Routine: encryption worker %d - stopped", id) device.log.Verbosef("Routine: encryption worker %d - started", id) - for elem := range device.queue.encryption.c { - // populate header fields - header := elem.buffer[:MessageTransportHeaderSize] + for elems := range device.queue.encryption.c { + for _, elem := range *elems { + // populate header fields + header := elem.buffer[:MessageTransportHeaderSize] - fieldType := header[0:4] - fieldReceiver := header[4:8] - fieldNonce := header[8:16] + fieldType := header[0:4] + fieldReceiver := header[4:8] + fieldNonce := header[8:16] - binary.LittleEndian.PutUint32(fieldType, MessageTransportType) - binary.LittleEndian.PutUint32(fieldReceiver, elem.keypair.remoteIndex) - binary.LittleEndian.PutUint64(fieldNonce, elem.nonce) + binary.LittleEndian.PutUint32(fieldType, MessageTransportType) + binary.LittleEndian.PutUint32(fieldReceiver, elem.keypair.remoteIndex) + binary.LittleEndian.PutUint64(fieldNonce, elem.nonce) - // pad content to multiple of 16 - paddingSize := calculatePaddingSize(len(elem.packet), int(device.tun.mtu.Load())) - elem.packet = append(elem.packet, paddingZeros[:paddingSize]...) + // pad content to multiple of 16 + paddingSize := calculatePaddingSize(len(elem.packet), int(device.tun.mtu.Load())) + elem.packet = append(elem.packet, paddingZeros[:paddingSize]...) - // encrypt content and release to consumer + // encrypt content and release to consumer - binary.LittleEndian.PutUint64(nonce[4:], elem.nonce) - elem.packet = elem.keypair.send.Seal( - header, - nonce[:], - elem.packet, - nil, - ) - elem.Unlock() + binary.LittleEndian.PutUint64(nonce[4:], elem.nonce) + elem.packet = elem.keypair.send.Seal( + header, + nonce[:], + elem.packet, + nil, + ) + elem.Unlock() + } } }